Nasal mask



FIG. 1 is a front perspective view of a nasal mask showing a first embodiment of our new design;

FIG. 2 is an enlarged front view thereof shown in isolation;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a bottom perspective view thereof;

FIG. 9 is a front perspective view of a nasal mask showing a second embodiment of our new design;

FIG. 10 is an enlarged front view thereof shown in isolation;

FIG. 11 is a rear view thereof;

FIG. 12 is a top view thereof;

FIG. 13 is a bottom view thereof;

FIG. 13 is a left side view thereof;

FIG. 14 is a right side view thereof;

FIG. 15 is a bottom perspective view thereof; and,

FIG. 16 is a bottom perspective view thereof.

The broken lines represent environmental structure of the nasal mask and do not form a portion of the claimed design. 

CLAIM The ornamental design for a nasal mask, as shown and described. 